Apple and Google have defined strict design requirements to ensure that all passes look stunning and remain consistent across devices. Even though you may design a pass using the PassKit web designer, the final appearance in Apple Wallet and Google Wallet is determined by how these platforms interpret and render the pass. PassKit translates your design into code that Apple and Google recognize, and this code is then displayed appropriately in their wallet apps.

The limitations on image and font size, as well as other design elements, are not arbitrary but are dictated by the technical and design frameworks of Apple and Google. These constraints ensure that passes are functional, visually consistent, and compatible across a wide range of devices and platforms. If a feature or design element is not possible in the PassKit Designer, it is because it falls outside the boundaries of what Apple and Google support.

By adhering to these standards, PassKit ensures that your pass can be accepted into Apple Wallet, Google Wallet, and any other future wallets that may become mainstream. For more details, you can refer to the Wallet Pass Design Limitations article.

In summary, the design limitations exist to provide a seamless and reliable user experience while maintaining compatibility and consistency across platforms.